Keyhole guard



1932- s. F. ALBlNO 1,842,642

KEYHOLE GUARD Filed May 7. 1931 SEW i e I I dbtomuq Patented .Ian. 26, 1932 PATENT OFFICE SAMUEL F. ALIBINO, OF SYRACUSE, NEW YORK KEYHOLE GUARD Application filed May 7, 1931. Serial No. 535,789.

The present invention relates to door locks and more particularly to a safety device in combination with a conventional door look by means of which a key or other means it cannot be inserted into the look from the :lpposite side of the door for unlocking the oor.

An object of this invention is to provide a safety device of this kind of relatively simple to but at the same time practical construction which may be inserted in any conventional key hole from one side of the door, the device being so constructed as to project into'the lock and having locking means by which the device cannot be pushed out of the look from the opposite side of the door.

Another object of this invention is to provide a device of this kind which may be used in combination with a key disposed within the look so as to prevent the turning of the key from the opposite side of the lock.

The above and various other objects and advantages of this invention will in part be described in and in part be understood from the following detailed description of the present preferred embodiment, the same be iug illustrated in the accompanying draw ings, wherein Figure 1 is a detail perspective View of a device constructed according to the preferred embodiment of this invention;

l igure 2 is a detail side elevation of the device mounted within a conventional looking mechanism;

Figure 3 is a top plan view of the base plate, and

Figure 4 is a top plan view of the hinged looking plate.

Referring to the drawings wherein like numerals of reference designate correspond ing parts throughout the several views, the numeral 10 designates generally a locking mechanism for a door or closure member which is provided with an escutcheon plate 11 having a key opening 12 therethrough which is in alinement with the key opening 18 of the locking mechanism 10.

In the conventional door looks, it is possible to readily pick the looks or to turn a key disposed within the lock from the opposite side thereof by an instrument inserted within the key hole. In order to prevent either the insertion of a master key or an instrument for removing the conventional key from the look, I have provided an elongated plate 14 which at one end thereof is provided with a curved portion 15 and at the opposite or inner end with an aperture 16 for receiving a flexible member 17 in the form of a chain or the like so as to permit the securing of the plate 14 on a door knob or the like. The curved or outer end 15 of the plate 14 is adapted to be projected into a key hole and into the key opening of a lock, the offset portion 15 being provided so as to substantially occupy the entire space within the key hole which is normally provided for the insertion of the key. This offset portion 15 will prevent the projection or insertion of an instrument or master key from the opposite side of the door or the lock. v

In order to secure the plate 14 within the key hole 12 of the esoutcheon plate 11, I have provided a pivoted plate 18 which is of a length shorter than the plate 14 and provided at the outer end thereof with hinged members 19 engaging in slots 20 of the base plate 14 so as to rockably secure the looking plate 18 on the base plate 14.

The inner end of the plate 18 is provided with a serrated portion 21 and this inner end may be outwardly curved so as to facilitate the movement of the plate 18 toward the base plate 14 on the hinge 19. In order to resiliently mount the hinged locking plate 18 on the base plate 14, I have provided an expansible spring 22 which is disposed between the plate 18 and the base plate 14. The base plate 14 is provided on the opposite sides thereof with upwardly extending flanges 23 and in like manner, the hinged locking member 18 is also provided with depending flanges 24 which engage about the peripheral portion of the spring 22 and hold the spring 22 against inward movement. These flanges 23 and 24 are disposed on the plates 14 and 18, respectively, in inwardly converging relation so as to wedge the spring 22 therebetween and prevent inward movement thereof.

The base plate 14 is provided with an elongated stop arm 25 which extends upwardly from the body of the plate and at the upper end thereof is provided with an inwardly extending tongue 26 engaging the top or upper surface of the locking plate 18 so as to limit the swinging movement of this plate 18. The plate 18 may lie-provided with a notch orrecess 27" within which the stop member 25 may engage.

A locking tongue--28 is struck fromthe body of the plate 18 at a point intermediate the opposite ends thereof, this: locking tongue being rearwardly or inwardly directed so as to provide a locking member-which is adapted to engage the inner surface of the escutcheon plate 11 when the device has been inserted'within the key hole. By mounting the locking tongue on the plate 18 in angular relation thereto, the insertion of the device within the key hole is facilitated inasmuch as the inward movement ofthe device within the key hole will force the hinged plate I 18 inwardly until the looking tongue 28 has passed the marginal edgesv of'the key hole 12 in the escutcheon plate whereupon the spring 22 will force the hinged locking member 18 V outwardly so that the inner or free end of the tongue 28 will engage the inner face of the escutcheon plate 11.

The base plate 14 may be of any desired width, that is, it may be of a width equal to the Width of the tongue ofIthe key or it may berof a. width equal to the entire length of the keyhole. lVhere the base plate 14 and the locking plate 18are of a width only equalto, the locking, tongue of'the key or keyhole, the key may be first inserted within the. key holeand the lockand turned substantially 45 whereuponlthe device. may be insertedwithinthat portion of the key hole 7 disposed below the shaft of the key. The offset outer end portion will bedisposed substantially within the body of the lock and due. to the fact that" this offset portion 15 occupies practically the entire width ofthe key hole within the lock, it. will be impossible to insert a key from the opposite side of the lock or to turn the already mounted key within the look by an instrument inserted from the. opposite side thereof. Through the. provisionof. the stop member 25, it is also impossible to pull the base plate 14through. the key hole from the opposite side by an instrument inserted" from the opposite side, this stop member 25.being of a length in excess of the width of the key hole.

It is, of course, understood that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by,thescope of the following claims.

I claim Y 1. A key hole guard of the character de scribed comprising an elongated plate, a locking plate hinged to said elongated plate, a spring interposed between each of said plates, means carried by each of said plates for holding said spring against longitudinal movement, and a locking tongue projecting outwardly from the body of said locking plate and adapted for engagement with an escutcheon platewwhereby to hold the device within the key hole against movement.

2; Azkey hole guard of the character described comprising an elongated plate having anoifset outer end portion, a locking plate hinged'to said elongated plate intermediate. the opposite ends thereof, a spring interposed between each of said plates and. normally urging; said locking plate away from saidelongated plate, converging flanges. carriedby each of said plates and engag ng said spring whereby to hold the ends ofsaid spring on. each ofsaid plates, and alocking memperoliset, from the body of'said locking plate; ,7

l A key hole guard of the character described comprising an elongated plate, a locking plate hingedly mounted on said elongated plate intermediate the ends thereof, a spring "lnterposedbetween said'elon'gated plate and,

said locking plate, means for securing said spring toeach of. said plates, at stop member carried said-elongated plate and engagin g :said locking .plate whereby. to limit the swinging .movement offsaid locking p1ate,/ -100 and a locking-tongue offset from the body of saidlockingplate. p Y

4. .A key hole guard of. the character described comprising'an elongated'plate, an offset member securedjto. the outer end of: saidplate, a lockingplate hingedly secured .tosaid elongated plate intermediate the ends thereof, an expanding spring interposed between each of saidplates, inwardly convergin-g flanges carried byleaoh of said platesand; engaging said spring whereby to holdsaid springzagainstmovement: between the plates,

- a=StOp3 member integrallyformed with said elongated plate and engaging saidlocking opiates: whereby to limit the swinging ,movement of said locking plate, and. a locking tongue outstanding from the: body. of said locking plate intermediate the ends thereof.

5. A key guard of the character'described comprising an elongated bar adapted to be disposed in akeyhole, said bar having a curved end-portion disposed within the key holeto prevent insertion of a member'in the opposite end of. the key hole, and'a barlocking inember carried by the bar intermediate the endsthereoflandpositioned in divergent relation to the adjacent. endof thelbar, said locking;,member having means whereby to prevent movementofthebarin the key hole .130

unaccompanied by movement of the locking member toward the bar.

*6. A key guard of the character described comprising an elongated bar having an oifset end portion adapted to be positioned with in a key hole, and a yieldable bar locking member carried by the bar intermediate its ends and adapted to releasably lock said bar in a key hole.

In testimony whereof I hereunto aflix my signature.

SAMUEL F. ALBINO. 

